United States. Peak fertilizer use. Beginning in 1999, agriculture began a sharp and steady decline in the amount of fertilizer and water used, along with a decline in cultivated area, despite the continued steady increase in tons of fertilizer each year, thanks to higher yields per hectare, thus reducing environmental impact. Peak fertilizer use occurred in 1999. The construction industry experienced a similar phenomenon: bricks, cement, sand, gravel, wood, and paper peaked in 2007, and then began to decline as a whole. From 2000, consumption of aluminum, nickel, copper, steel, and gold began to decline dramatically in the United States, despite continued growth in GDP. By 2020, consumption of these raw materials will return to the levels of the mid-1970s.
